Oil well pumping unit



Sept. 28, 1943. F. A. GRUETJl-:N

OIL WELL PUMPING UNIT Filed -April 28, 1941 E .Elv

rvu. m O T. T. A

Patented Sept. 2.8, 19543 ou. WELL rUMPmG rUNIT l Frederick vA. Gruetjen, Milwaukee, Wis., assigner to A. 0. Smith Corporation, Milwaukee, Wis., a, corporation of New York Application April 2s, 1941, serial No. 390,782 16 Claims. (Cl. 10S-45) and the entire unit is submerged beneath the crude oil at the bottom of the well.

In this type of unit there has been considerable diiculty in loss of power lluid, and also in contamination of the power uid by sand and other constituents from the crude oil.

The principal object of the present invention is to maintain'the required qua `:tity of clean power fluid over a substantial period of operation of the pump.

A more specific object is to prevent loss of power uid.

Another object is to prevent injurious contamination of the power `fluid and to provide for its replenishment by clean fluid in case of loss.

lIn accordance with the invention the circuit of the power uid is 'hermetically sealed with the exception of the opening through which the uid motor piston operates to drive.the crude oil pump, and suitable'packings are provided n on the piston rod with a bleeder through the housing from between two groups of packing to the reservoir for power fluid.

In another phase of the invention a second bleeder is employed between two groups of packing at the lower end of the piston rod near the crude oil pump, leading to the well space outside of the housing.

principles of the inq A pump employing the drawvention is illustrated in the accompanying ing .in which:

Figure 2 shows the detail construction of the packing intermediate the fluid motor 9 and crude oil pump I0. In it the fluid motor 9 and crude oil pump I0 are shown as havinga common piston rod II.

The upper end of the housing I is sealed so that there is no chance for power fluid to escape except-downwardly along piston rod II and into the crude oil pump I0.

In carrying out the present invention, it is preferable to employ four sets of packings around the piston rod, as well as sandfscrapers I2 at the lower end for preventing sand from following upward along the rod from the crude oil pump.

'The packings are made up of annular rings of impregnated fabric or molded oil proof'composition pressed together between spring metal rings with their edges directed against the' piston rod at an angle. The lower two sets I3 and I4 of packing have their edges extending downwardly and inwardly against the piston rod, while the 'upper two sets I5 and I6 of packing have their edges extending upwardly and in-f wardly against the piston rod. This type of' packing and arrangement has been found to be most eiective in preventing upward leakage of crude oil from the crude oil pump and down- Figure 1 is a schematic longitudinal section showing the unit in a well, and

Fig. 2 is a longitudinal central section through the'pertinent part of the unit illustratingthe invention.

Referring to Figure l the pumping unit comprises a housing I suspended by a delivery pipe the housing usually being 2 or' cable in a well 3,

the bottom electric motor 5 at' ward leakage of clean power oil from the uid motor. i

In order. to catch any clean power oil which may leak downwardly past the upper packing I5,` a small annular recess I'I is provided in the packing housing facing the piston rod and between packings I5 and I6. This recess I1 is connected by a passage I8 to the reservoir Ii either above or below the level of oil therein, Any build up of pressure of oil in the recess Il from the fluid motorV will tend to force the leakage oil Aback up inte the'reservoir.

In this system packing I5 works to prevent leakage of 'oil from the motor in which very high uid pressures are used, while packing I6 works only to prevent leakage by reason of the pressure developed by the head of oil in reser- Should there be a tendency for power iiuid to leak past packing IB, an additional feature of the present invention provides a counterpressure of fluid b elow thetpacking` equal to or greater than that normally above it. This is obtained by the pressure of crude oil tending to lleak pas't packings I3 and I4' from the crude oil pump. lThis pressure would normally be equal to the head of oil in the delivery pipe 2, extending the f-ull depth of the well.

Since this counter pressure would be so great as to force crude oil past the packings and effect complete filling of the housing, with possible danger of contamination, a second feature of the invention comprises the providing of an annular recess I9 in the packing housing facing the piston rod between packings I3 and I4 and connecting the recess with-the space in the well outsidejof the housing by means of a passage 20. In this way the pressure of crude oil on the packing I4 will be no greater than the head of oil in the well as all oil leaking past the packing I3, due to the head of oil in the delivery pipe 2, is vented at port 20.

A iilter 2| or other means may be provided in passage 20, to keep any oil which ows in from the well through the passage free from sand or to entirely prevent the flow of oil inwardly. Normally, the leakage of oil past packing I3 due to the great pressures developed in the'crude oil pump will insure that dirty oil will not seep in through passage 20. The head of oil in the well, however, will normally be suiiicient to maintain a fluid pressure4 below packings I 4 and I6 greater than that above, and consequently there will be no tendency for leakage of power oil downwardly past the packings.

The port 20 might be connected to bleed a space between packings 'I4 and I 6 or either packing I4 or I6 or, in some instances, both might be eliminated. Any tendency for leakage of crudeoil into the power oil system from below merely raises the pressure in the reservoir 6 until a balance is reached that prevents further leakage. Where it is desired to retain a gas space in the reservoir, the latter may be charged under pressure sufficient to prevent any infiltration of crude oil into the system.

The detail construction of the packings herein illustrated is set forth and claimed in an application, Serial Number 390,783 filed on even date herewith by the present inventor. An improved construction for carrying out the present invention is illustrated and claimed in application, Serial No.7390,'781, led on even date herewith by the present inventor.

Various embodiments of the invention may be employed within the scope of the accompanying claims.

The invention is claimed as follows:

1. In an oil well pumping unit, a. reciprocating crude oil pump disposed vertically at the bottom of the well, a reciprocating iuid motor disposed above the pump, a common piston rod connecting the pump and motor for driving the former by the latter, a substantially closed circuit for power iiuid to operate said motor, packing means'encircling said piston rod between said motor and pump to substantially prevent leakage of power fluid along said rod from the motor, means for returning leakage power iluid from an intermediate point in said pac-king means to the power fluid circuit on the exhaust side of the motor, and means including said crude oil pump for maintaining a fluid pressure below said packings which is at least equal to the fluid pressure of said leakage power fiuid'to prevent leakage of the latter beyond said intermediate point in the packing.

2. In an oil well pumping unit, a reciprocating crude oil pump disposed vertically at the bottom of the well, a reciprocating uid motor disposed above the pump, a common piston rod connecting the pump and motor for driving the former by the latter, a substantially closed circuit for power fluid'to operate said motor, packing means encircling said piston rod between said motor and pump to substantially prevent leakage of power fluid along said rod from the motor, means for returning leakage power fluid from an intermediate point in said packing means to the power iiuid circuit on the exhaust side of the motor, and means for bleeding leakage of crude oil from said pump from an intermediate point in said packing below said iirst named intermediate point to the space in the well outside of the unit.

3. In adevice of the class described, a iiuid motor having a reciprocating piston with a piston rod, a power pump for supplying fluid under pressure to said motor, a reservoir for power iuid for receiving the exhaust from said motor and supplying iiuid to said power pump, an electric motor for driving said power pump, a hermetlcally sealed housing enclosing the above named elements and through the end wall of which the piston rod of said fluid motor reciprocates, packing means encircling said piston rod, and means in said housing for returning power uid which may have leaked past said packingto the reservoir.

4. In. a device of the class described, a uid motor having a reciprocating piston with a piston rod, a power pump for supplying iluid under pressure to said motor, a reservoir for power fluid for receiving the exhaust from said motor and supplying fluid to said power pump, an electric motor for driving said power pump, a hermetically sealed vhousing enclosing the above named elements and through the end wall of which the piston rod of said iiuid motor reciprocates, packing means encircling said piston rod, an annular recess in the packing housing wall intermediate sections of packing, and a passage in the wall of said Vhousing and connecting said recess to the reservoir.

5. In a device of the class described. a fluid motor having a reciprocating piston with Va piston rod, a power pump for supplying iiuid under pressure to said motor, a power iiuid reservoir for receiving the exhaust from said motor and supplying iiuid to said power pump, an electric motor for driving said power pump, a hermetically sealed housing enclosing the above named elevments and through the end wall of which the motor having a reciprocating piston with a piston rod, a power pump for supplying iiuid under. pressure to said motor, a reservoir for .power iiuid for receiving the exhaust from said motor and supplying fluid to said power pump, an electric motor for driving said power pump, a hermetically sealed housing enclosing the above named elements and through the end wall of which the piston rod of said iiuid motor reciprocates, said reservoir having a gas space above the fluid level therein and in which the gas is charged under a predetermined pressure, packing means encircling said piston rod, means for returning power fluid which may have leaked past said packing to elements and through the end wall of which the.`

piston rod of said uid motor reciprocates, said reservoir having a gas space above the fluid level therein and in which the gas is charged under a predetermined pressure, packing means encircling said piston rod, means for returning power uid which may have leaked past said packing to the reservoir, and a passage connecting a lower intermediate point in the packing to the outside well space to relieve the pressure-from below the packing due to the crude oil pump. I

8. In a `device of the cl'ass described, a uid motor having a reciprocating piston with a piston rod, a power pump for supplying fluid under pressure to said motor, a reservoir for power uid for receiving the exhaust from said motor and supplying fluid to said power pump, an electric motor for driving said power pump, a hermetically sealed housing enclosing the above named elements and throughthe end wall of which the piston rod of said iiuid motor reciprocates, packing means encircling said piston rod, means for returning power uid which may have leaked past said packing to the reservoir, and a passage connecting a lower intermediate point in the packing to the outside well space to relieve the pressure` from lbelow the packing due to the crude oil pump.

, 9. In an oil well pumping unit, a crude oil pump disposed vertically at the bottom of the Well, a fluid motor disposed above the pump, a driving connection between said motor and pump lhaving packing means to prevent intermingling and leakage of power uid and crude oil, a substantially closed circuit for power fluid to operate said motor, said packing being divided and 'having intermediate bleeder means for returning leakage power` iluid to the power iiuid circuit, and means for supplying to said power iiuid circuit clean crude oil to maintain the supplyof power uid.

10. In an oil well pumping unit disposed at the bottom of the well, a crude oil pump, a fluid motor connected to drive said pump, a closed circuit for power fluid to drive said motor, a packing for the connection between the motor and pump subjected at one end tothe pressure of said power uid in the motor intake and at the other end to the pressure of the crude oil in the pump exhaust, and means intermediate the ends' of said packing for relieving leakage ud from said pressures.

11. In an oil well pumping unit disposed at the bottom of the well, a crude oil pump, a uid motor connected to drive said pump, "a closed circuit for power fluid to drive said motor, a packing for the connection between the motor and pump subjected at one end to the pressure of said power fluid in the motor intake'and at the other end to the pressure of the crude oil in the pump exhaust, said packing being divided and having a passage connecting an intermediate recess therein to the exhaust side of said motor.

12. In an oil well pumping 'unit disposed at the bottom of the well, a crude oil pump, a uid motor connected to drive said pump, a closed ycircuit for power fluid to drive said motor, a packing for the connection between the motor 'and pump subjected at one end to the pressure of said power fluid in the motor intake and at the other end to the pressure of the Vcrude oil in the pump exhaust, said packing being divided and having a passage connecting an intermediate recess therein` to the intake side of said crude oil Dump.

13. In an oil well pumping unit disposed at the bottom of the well, a crude oil pump, a :duid motor connected to drive said pump, a closed circuit for power iiuid to drive said motor, a`l

packing for the connection between the motor and pump subjected at one end to the pressure of said power uid in the motor intake and at the other end 'to the pressure of the crude oil in the pump exhaust, said packing. being divided and having passages connecting an intermediate point therein to the exhaust side of said motor and the intake side of said pump.

14. In a deepwell pumping unit having a reciprocating pump driven by a reciprocating hydraulic motor by means of a piston rod common to both, means for preventing loss of power fluid for driving said' motor and of admixture of crude oilv with the power fluid, comprising a series of packingssurrounding said piston rod and disposedA to prevent the leakage of crude oil along the rod from said pump and the leakage of power fluid along the rod from said motor, a take-off for crude oil which may leak'past the set of packing nearest the pump, a similar takeo for power uid which may leak past the set of packing nearest the motor, there being at least .one set of packing between the two takeois, means to return the crude oil from said crude oil take-off to the -main body of crude oil, and means to return the power duid from said power uid take-off to the main body of' power iiuid.

15. In a deep well pumping unit having a reciprocating pump driven by a reciprocating hydraulic motor by means of a piston rod common to both, means for preventing loss of power fluid for driving said motor and of admixture of crude oil with the power fluid, comprising a series of packings surrounding said piston rocl and disposed to prevent the leakage of crude oil along the rod from said pump and the leakage of power fluid along the rod from said motor, a take-oir for crude oil which may leak past` the set of packing nearest the pump, and a similar take-off for power uid which may leak past the set of packing nearest the motor, there beingat least one set of packing between the two take-offs.

16. In a deep Well pumping unit having a reciprocating pump driven by areciprocating motorby means of a piston rod, means for preventinguid being pumped from leaking along the piston rod to the motor, comprising a' series of packings surrounding said piston `rod and disposed to prevent the leakage of uid therealong from the pump, a take-off for uid which may leak past the rst set of packing nearest the pump, and means to return the uid from said tafke-oi to the main body of fluid being pumped.

EREDERICKA. (sRrJrrrJEN.l 

